|Mostafa, S - MISSISSIPPI STATE UNIV|
|Varco, J - MISSISSIPPI STATE UNIV|
Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 12, 2005
Publication Date: April 1, 2006
Citation: Adeli, A., Mostafa, S.M., Varco, J.J., Rowe, D.E., Sistani, K.R. 2006. Effects of swine lagoon effluent and commercial fertilizer applications on phosphorus status of an acid and alkaline soil. Communications in Soil Science and Plant Analysis. 37:2011-2030. Interpretive Summary: The confined swine feeding operation in Mississippi generated large quantities of wastes which is typically flushed into anaerobic lagoon to facilitate digestion. To prevent lagoon overflow, swine effluent is applied to adjacent croplands for hay production. Long-term land application of swine effluent can result in elevated levels of soil P. Repeated manure applications decreased the P sorption capacity of the surface soil which increased accumulation of loosely bond P in the soil and increases potential for P movement by runoff. The potential for P transport from land irrigated with swine lagoon effluent is a critical concern with confined animal feeding operations. It has been reported that animal wastes contained P fractions that were not susceptible to adsorption by a calcium carbonate layer in the soil and would thus be more likely to leach deeper into the soil than fertilizer P. Thus, identification of P fractions in soils treated with swine lagoon effluent is very important since a close relationship exists between the chemical forms of P in the soils and the amount of P desorbed from the soils. Soil P fractionation gives an idea about the soil P supplying capacity to plants. Also soils vary widely in their P sorption-desorption properties. Likewise, soils in Mississippi (such as Vaiden and Okolona) may also show diversity in their P retention and P adsorption-desorption properties. Therefore, soil specific data on soil P levels, P adsorption-desorption capacities, and soil P fractions are of the utmost importance in developing an agronomically and environmentally sound P management plan from animal waste application. Limited data is available on sorption, desorption, and fractionation of soil P fractions for Mississippi soils when these soils receive anaerobic swine lagoon effluent for hay production. This study was conducted to investigate the fate of swine lagoon effluent P compared to commercial fertilizer P in two soils contrasting in pH.
Technical Abstract: Two separate field experiments were conducted to evaluate the effects of swine lagoon effluent relative to inorganic fertilizer on the phosphorus sorption, desorption and soil test P of an acidic Vaiden (very fine, montmorillonitic, thermic, Aquic Dystrudert) and an alkaline Okolona (fine, montmorillonitic, therimic, Typic Chromudert) silty clay soils. In each soil, a randomized complete block design with a factorial arrangement of treatments replicated four times was used. Cumulative swine lagoon effluent P rates for the year 1994 through 1996 were 0, 59, 121, and 175 kg P ha-1 on the Vaiden soil, and 0, 72, 148, and 223 kg P ha-1 on the Okolona soil. Less swine effluent P was applied to the Vaiden soil due to the establishment of bermudagrass in 1995. Commercial P fertilizer at rates equivalent to swine effluent P application were also included. For both soils, P content of the 0-5 cm depth was increased with increasing application rates of swine effluent and inorganic P fertilizer. No significant difference in soil P content was observed for both P sources. Desorbed P in the Okolona soil was 1.20 mg P kg-1 and in the Vaiden soil was 0.59 mg P kg-1. In the Vaiden soil, P adsorption approached the maximum for equilibrium P concentration greater than 600 mg L-1. Okolona soil displayed a linear adsorption potential with application of P. NH4Cl-P and HCl-P fractions had the greatest percent increase compared to the check due to either fertilizer or swine effluent application to the Okolona and Vaiden soils, respectively. In each soil, results indicated that no significant differences in P content was obtained between swine lagoon effluent and commercial fertilizer, suggesting that both P sources had similar effect on soil P after 3 years of application.